最新刊期
卷 ， 期 2 ， 1998
- 摘要：Polystyrene/montmorillonite nanocomposites were prepared by melt intercalation.Their structure and properties were studied with X ray diffraction and differential scanning calorimetry.X ray diffraction results proved that polystyrene melt could not be intercalated in original Na+ montmorillonite,but could be intercalated in organically modified montmorillonite.The gallery distance of organo montmorillonite increased from 2.16nm to 3.25nm after intercalation of polystyrene chains.The presence of the alkylammonium cations is the galleries of organo-montmorillonite rendered the hydrophilic montmorillonite organophilic.The role of alkylammonium cations was to lower the surface energy of the inorganic montmorillonite and improve the wetting characteristics with polystyrene.The glass transition temperatures of polystyrene/organo-montmorillonite composites for various heating time were all 1～2°higher than that of bulk polystyrene.Also the enthalph changes at glass transition of polystyrene/organo-montmorillonite were larger than that of bulk polystyrene.The results indicated that polystyrene/organo-montmorillonite hybrid formation required no additional processing time than currently required by conventional polymer processing techniques.
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发布时间：2021-03-19 - 摘要：The inverse emulsion of sodium acrylate was stabilized with an anionic emulsifier (sodium 12 butinoyloxy 9 octadecenate). The polymerization was initiated with γ ray.The particle sizes of the inverse emulsion before and after polymerization were observed with scanning electron microscope.The effect of changing dose rate during polymerization on polymerization rate was also determined to understand the nucleation mechanism.These observed results hinted that the polymerization nucleates in monomer droplet.As in the inverse emulsion syailized with Span 80,the expression of polymerization kinetics was similar to that in susoension polymerization.At most cases,the molecular weights of polymer were smaller than that produced in systems stabilized with Span80.
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发布时间：2021-03-19 - 摘要：Conductivity,thermal stability and electrochemical stability of a polymeric gel electrolyte of LiClO 4 ethylene carbonate PMMA were measured.The inonic conductivity as a function of temperature followed the Vogel tammann fulcher equation.When LiClO4 concentration was 15mol/L,PMMA wt% was 35,the electrolyte had the highest ionic conductivity,δ=1.92×10-3S/cm,good transparency and stability in air and some adhesivity.Thermal stability was high(wt% change was 3.28) under 102℃.It was electrochemically stable,ie.△V=4.5V.So it can satisfy the needs of solid state eletrochromic "Smart"windows.
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发布时间：2021-03-19 - 摘要：The atactic polystyrene (a PS) was slowly uni axial stretched at temperature 30℃ above its Tg.The resulting samples were characterized by a series of measurements.The results of IR dichroism,WAXD and optical birefringence all showed that in the segmental sense the samples were nearly isotropic,while the global orientation was remained,this can be indicated by the large elastic recovery of samples heated to temperatures above Tg.These samples showed large anisotropy in the solution swelling,the thermal expansion and stressstrain behavior.
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发布时间：2021-03-19 - 摘要：Silicone rubber/montmorillonite hybrids were synthesized by means of solution and melt mixing.The mechanical properties,thermal stability and solvent resistance of the hybrids were compared with that of silicone rubber filled by aerosilica.The results proved that montmorillonite could be dispersed in the silicone rubber matrix more uniformly by solution than by melt mixing.The resulting hybrid had properties close to that of aerosilica filled silicone composite.
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发布时间：2021-03-19 - 摘要：The norbornene/ethylene copolymerization was investigated by using Me2SiCp2MtCl 2(Mt=Zr,Ti)/MAO catalyst system. The copolymerization Kinetics was studied under different conditions. The copolymer was characterized by DSC and 13C-NMR methods. It was found the zirconocene has better catalyst ability for copolymerization of ethylene and norbornene than titanocene. Under similar feed ratio, the copolymers with high norbornene content and glass transition temperature were synthesized compared with literature.
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发布时间：2021-03-19 - 摘要：P(MMA MAA)/ladderlike PPSQ blends, in which PPSQ has a low or high molecular weight, were prepared by in situ copolymerization. Light transimissivity measurement, fluorescence, DSC techniques were used to study the miscibility, interactions of two components and structural transitions. The results indicate that P(MMA MAA) and PPSQ are completely miscible on a small scale of 200nm because of some strong hydrogen bonding interactions between molecules of P(MMA MAA) and PPSQ when the blends contain a small amount of PPSQ and that PPSQ with a low molecular weight has better miscibility with P(MMA-MAA)than that of PPSQ with higher Mw.Although compositions of the blends has little influence on Tg,Tf, of the blends almost increase with an increase of PPSQ content (PPSQ≤1%).Ball hardness and impact strength of all blend samples were also measured.
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发布时间：2021-03-19 - 摘要：The intermediate(Ⅰ),polymethylene bis(p-ethoxycarbonyloxy benzoates),was prepared from solbrol and hexandiol by melting transesterification reaction.The block copolyesters with different block length were synthesized from terephthaloyl dichoride,hexandiol and (Ⅰ).The structure and compositions of these block copolyesters were analysed by FTIR and H NMR.The liquid crystalline behaviors of the block copolyesters were characterized by DSC,POM.
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发布时间：2021-03-19 - 摘要：The adsorption of partial hydrolyzed polyacrylamide (PHPA) on aluminum magnesium hydroxide (AMH) possessing permanent positive charges and effects of degree of hydrolysis(α),pH, ionic strength and temperature have been studied. The presence of mutilayer adsorption of PHPA on AMH is found, and the amount of adsorption (A) decreases with increasing α of PHPA. With increasing pH the A of PHPA with lower α such as sample PHPA1 (α=2.4%) increases and however the A of PHPA with higher α such as samples PHPA2(α=10.8%)and PHPA3(α=41.2%)decrease.The presence of NaCl may reduce the A of PHPAl but may raise the A of PHPA2.The increase of temperature may raise the A of PHPA,which indicates that the adsorption processes studied are endothermic.The mechanism of adsorption has been discussed in the paper.According to the experimental results,in is inferred that the adsorptive force between flexible polymer moleculae and adsorbent has a optimum range in which the amount of adsorption is maximum.When the adsorptive force is too strong,the amount of adsorption will be lower because the sdsorbed flexible moleculae mey be spreed.Of course,when the adsorptive force is too weak,the amount of adsorption will be lower also.
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发布时间：2021-03-19 - 摘要：A conducting and transparent film of doped polyaniline was prepared by a dipping polymerization method.The electric and optic properities of the resulting film were measured as a function of oxidant,dopant,substrate,reaction time and temperature.In proper condition,for the 0.5μm polyaniline film,the conductivity at room temperature and the transmittance at 450～650nm can be achived of 1～5S/cm and 80%,respectively.The growth mechnism and structure composition of polyaniline film were discussed.
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发布时间：2021-03-19 - 摘要：The synthesis and free radical polymerization of the novel methacrylate monomer containing photochromic para nitroazobenzene group and the methacrylate monomer containing mesogenic group are described.The novel azo monomer and polymers were characterized by1H-NMR,IR,UV Vis,GPC,Elemental analysis,DTA and POM techniques.The polymers obtained from the copolymerization of the azo monomer and the mesogenic monomer are proved to be random copolymers and all of them show nematic liquid crystalline textures.The UV-induced trans/cis photoisomerization and the thermal back-isomerization were investigated for the azo monomer and copolymer 1 in solution and copolymer 1 in solid film and correlated with the structures of the compounds.The results indicate that both solutions of the azo monomer and the copolymer 1 and the condensed film of the copolymer 1 can undergo photoisomerization and thermal back-isomerization,and the environments of the azo group are mainly responsible for the above photochemical process.
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发布时间：2021-03-19 - 摘要：Five new polyester ligands were prepared by the condensation polymerization of diethylenetriaminepentaacetic dianhydride with PEG of various molecular weight (Mn).By the reaction of these macromolecular ligands with GdCl3·6H2O,the corresponding metal complexes were obtained.Preliminary results showed that the relaxivity of these macromolecular gadolinium complexes were higher than that of Gd(DTPA) which is widely used in clinical diagnosis.
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发布时间：2021-03-19 - 摘要：Polystyrene (PS) was completely immiscible with a liquid crystalline polymer (LCP),PHB/PET copolyester,and their blends had a distinctive two phase structure.Then PS was chemically modified by introducing sulfonic acid group onto its molecular chains.Thereafter the properties of LCP blends with modified PS,sulfonated polystyrene(SPS),taking five forms:acid form,Li,Na,Mn and Zn salt forms,were carefully characterized with the DSC and SEM.DSC results demonstrate that SPS is miscible with LCP evidenced by exhibiting only one composition dependent Tg.The LCP's Tg's calculated from the Fox Equation were about the same in blends at the studied composition.This means that the requirment of Fox Equation has been met,i.e.LCP is completely miscible with SPS.The miscibility enhancing is confirmed by SEM observations too.LCP/PS blends showed a distinct two phase structure .LCP blends and SPS with low SPS contents(25%)exhibited only a single very smooth texture,whereas those with high SPS contents(75%) had nanometer scaled droplets dispersed through the whole surface.Energy Disoersion confirmed the presence of sulfur-rich structures in those particles.
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发布时间：2021-03-19 - 摘要：The symthesis of interpolymer complex based on P(TM-co-AAM) and PAA was investigated.The effects of pH,cationic degree of cationic polymer and molecular weight of cationic polymer and PAA on the formation of complex were studied.The interaction between the different polymer chains was studied by FT IR,DSC and conductometric titration.The mechanism of formation and pH semsibility of complex were explained.
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发布时间：2021-03-19 - 摘要：The soapless emulsion copolymerization of methyl methacrylate (MMA) and n- butyl-acrylate (BA) with various ratios of MMA to BA in the presence of small amount of sodium methacrylate (NaMA) was studied.Increasing BA feed fraction results in a decrease of particle diameter,surface tension and viscosity of the latexes,and an increase of particle number,polymerization rate,surface charge density of the latexes and molecular weight of copolymer.The DSC thermogram of MMA/NaMA soapless latex copolymer (SLC) shows one glass transition temperrature(Tg),while that of BA/NaMA SLC shows two Tg.and those of MMA/BA/NaMA SLCs with the ratio of MMA to BA within 2:1～1:2 show 4Tg.The heterogeneity of copoymer composition for multiple Tg is ascribed to the assumption that the dissolved water in the sublayer surrounding the particle,enriched with-OSO-3 and -COO- groups,will cause the concentration gradients of MMA and BA monomers and phase separation.
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发布时间：2021-03-19 - 摘要：The paper described the modification of epoxy resin using a new prepolymer containing spiro orthocarbonate. It was found that the addition of prepolymer into epoxy resin system enhanced the conversion of epoxy groups and the Tg and thermal stability of the matrix were slightly reduced. The adhesive tensile and shear strength of the modified epoxy resin increased obviousely as the content of the prepolymer increased. The above observed phenomena were discussed, and the relationship between shrinkage and adhesive strength was investigated.
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发布时间：2021-03-19 - 摘要：Vapor HF cann't react with SiO2 at temperature of above 100℃.With the help of some polar compounds or superacids,which are called etching accelerators,the etching reaction may occur at the interface between SiO2 layer and photocrosslinked polymer film.The accelerators can be categorized into three groups:(1) tertiary amine compounds,which can form ammonium with HF to generate a high concentration of active fluorine anions.(2) organic compounds containing carbonyl,nitro,amino formacyl.These dipolar aprotic accelerators can activate HF to become an active necleophilic attacking reagent and make the etching reaction possible.(3) superacids,such as HBF4,HPF6 and HAsF6,which can be generated through the photolysis of photosensitive acid generators.Superacids can activate the leaving group and act as catalyst of the reaction.Polymer film can prevent the small molecular accelerator added in it from escaping.And the polymer carrying accelerating groups itself,which is called polymer accelerator,can act as film former and accelerator simultaneously.By using photochemical reaction,the area-selective etching reaction under polymer can be realized.
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发布时间：2021-03-19
Research Article
- 摘要：Self-reinforced Polymerized HDPE monofilament were prepared by die drawing process. According to Cox model for fiber composite and Gibson & Ward crystalline bridges′ model, the reinforced mechanism was discussed to reveal that the mechanical improvement of monofilament was due to the growth of needlelike crystal with larger aspect ratio or the increase of volume fraction of the crystalline bridge. Based on the experimental results obtained by DMA, DSC and SEM, the theoretical prediction was also analyzed and disussed,and found the theoretical values could well-explain the monofilament behavior.
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发布时间：2021-03-19 - 摘要：A vinyloxy monomer bearing of electronaccepting chromophore, p-vinyloxymethylbenzonitrile (VOMBN) and its saturated model compound, p-ethoxymethylbenzonitrile (EOMBN), were synthesized. VOMBN can be cationically homopolymrized by initiation of Lewis acid such as BF3·Et2O and copolymerized with maleic anhydride (MAn) using AIBN as an initiator. By fluorescence study, it has been found that the fluorescence in tensity of VOMBN is much lower than those of the copolymer P(VoMAn) and EOMBN at the same chromophore concentration.This means that a"Structural Self-Quenching Effect"(SSQE) has been also observed in VOMBN,which is attributed to the charge transfer interaction between the electron-accepting cyanophenyl chromophore and the electron-donating vinyloxy group in the same molecule upon UV irradiation.The fluorescence of EOMBN and P(Vo-MAn) can be quenched by a series of electron-rich vinyloxy compounds such as dihydrofuran (2H-furan),dihydropyran(2H-pyran),furan and ethyl vinyl ether(EVE),which do not have chromophore moieties.It is found that the higher the electron-donating ability of the quenchers which are represented by their ionization potentials,the higher the quenching efficiency.
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发布时间：2021-03-19 - 摘要：The thermosensitive hydrogels were prepared from the copolymerization of N-Isopropyl-acrylamide and N-vinyl pyridium tetrafluroborate(NVP.BF4) or N-methyl-4- vinyl pyridium methylsulfate (NMVP.CH3SO4) as cationic comonomers in the presence of methylene bisacrylamide(MBA) as crosslinking agent by means of γ-r and crosslinking agent on the properties of hydrogel especially the swelling ratio(SR) and sensitive temperature have been investigated The results show that theSRof the hydrogels will increase with the increasing the content of cationic monomer or decreasing the content of crosslinking agent.The sensitive temperature of the hydrogel will also increase with increasing the content of the cationic monomer but the content of the crossing agent seems to have no influence on it.
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发布时间：2021-03-19 - 摘要：The equilibrium melting temperature (T°m) of isotactic polypropylene (iPP) was studied by DSC technique for samples with different nucleating agents including calcium carbonate(CA), terephthalic acid(DB) and glutaric acid(WA). The (T°m) values of α modification iPP crystals obtained for samples with different nucleating agents were found to be within a narrow temperature range of 488～492K, almost independent on the nucleating agents.
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发布时间：2021-03-19 - 摘要：A novel poly(methyl methacrylate-co-vinyl acetate) / poly(ethylene-co-vinyl acetate) (poly(MMA-co-VAc)/EVA) alloy with temperature dependent optical properties was prepared by radical copolymerization induced spinodal decomposition(SD) in the mixture of MMA/VAc/EVA. The structural development during copolymerization was investigated by time resolved light scattering(TRLS) and scanning electron microscopy (SEM). As the copolymerization of MMA and VAc proceeded, phase separation took place via SD. This was supported by the characteristic change in light- scattering profiles with recation time. SEM photographs show that the phase separated structure is isolated poly(MMA-co-VAc) rich domains dispersed in EVA rich matrix.The optothermal properties of poly(MMA-co-VAc)/EVA alloy were abserved by transmittivity measurement, which the increase of temperature and vice varsa.Hence,poly(MMA-co-VAc)/EVA alloy is of potential use in applications such as temperature-controlled optical devices.
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发布时间：2021-03-19 - 摘要：Results are presented which include the synthesis, characteriation and electroluminescence performance of a new type of conjugated polymer, poly(2,5 diphenyl 1,3,4 oxadiazolyl) 3,3' vinylene(M PPV). In order to synthesize compound (A), two reaction routines were chosen, but experimental result showed that routine(1) was much more promising than that of routine(2). A light emitting diode with the structure of ITO/M PPV(80nm)/A1(150nm) is driven at about 6V and has a peak emission wavelength of 470nm, while the LED constructd using PPV(ITO/PPVA1) emitted yellow light.The most likely explanation on the differece is that a decrease in the conjugation length of the heterocycle-substituted PPV(M-PPV）increases the band gap to values higher than that of PPV,resulting in a blue shift in the emission apectrum and this is in agreement with the result determined by XPS technique.
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发布时间：2021-03-19 - 摘要：Cumene and other derivatives of benzene can form reversible contact charge transfer complexes (CCT) with O2, but due to the influence of the space structure of polystyrene (PS) such as steric or electronic effect caused by the neighboring benzene ring, the O2 CCT of PS is irreversible. High molecular weight PS(HPS) gives its maximum absorption wavelength of O2 CCT at 278.4nm, but low molecular weight PS(LPS) at 295.6nm as it has a similar structure of styrene due to a double bond at one end of its chain which results in the red shift of O2-CCT absorption.The CCT formed between PS and O2 has been considered as the initial state of the dark oxidation and it is proposed that PS as like the model compound cumene undergoes dark oxidation through O2-CCT,CTC,H+transfer,free radicals in cage and the formation of hydroperoxides.
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发布时间：2021-03-19
Research Bulletin
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